Method of and means for burning pulverulent fuels



March 24, 1925 C. W. LOTZ METHOD OF AND MEANS FOR BURNING PULVERULENTFUELS Filed Jan. 9, 1920 Wi'trzeaaes INVENTOR, omwi 1 v v ATTOR Y.

Patented Mar. 24, 1925.

UNITED STATES PATENT OFFICE.

CHARLES W. LOTZ, OF PdTTSVILLE, PENNSYLVANIA.

' Application filed January 9, 1920. Serial No. 350,476.

To all 107mm it. may concern:

Be it known that I, CHARLES W. Lorz, a

citizen of the United States of America, re

siding at Pottsville, in the county of Schuylkill and State ofPennsylvania, have invented certain new and useful Improvements inMethods of and Means for Burning Pulverulent Fuels, of which thefollowing is a specification.

My invention relates to improvements in the method of and means forburning pulverulent. fuels and especially such fuels as are deficient involatile contents, such as anthracite, culm and coke breeze, forexample.- The object of myv invention is to utilize such fuelssuccessfully in commercial practice, to secure certain economies andbetter control in the combustion of such fuels, and enable the user tooperate a furnace under widely divergent conditions of load.

It is desirable to maintain a relatively cool bottom or zone in furnacesof the type here considered, wherein the resultant ash may be cooled.Likewise, it is desirable, if not necessary, to'maintain the combustionin space within such furnace, i. e., above the bottom and away from itsside walls, in order to prevent the otherwise destructive actionresulting from. the intensely heated fuel cloud impacting within thecombustion chamber. I

When prior furnaces of the type herein preferred must 'be operated atexcessive rating, slagging of the bottom inevitably results. This isoccasioned by reason ofthe fact that it is impracticable to build andoperate a furnace with a combustion chamber of sufficient height toinsure a relatively cool bottom under periods of extreme load. Theformation of slag in any quantity directly upon the bottom of thecombustion chamber, lIOWGVGIQ iS highly undesirable for the reason thatthe furnace must shortly be sliut down and the slag removed, althoughonly with great difiiculty when solidified in a coherent mass.

Accordingly, I have devised a mode of operation and means for overcomingthe disadvantages named, while attaining the concurrent advantages ofcooling the slag in relatively small masses and preheating thecombustion-supporting air supply of the furnace. Briefly stated, myimprovements contemplate the introduction of the finely pulverized lowvolatile fuel downwardly within the combustion chamber, in the form of athin curtain and with a limited air supply, which curtain is subjectedto the intense heat of the deflagrating and closely adjacent revertingflame burning in space within said chamber. An adjacent slagging wall,beneath which an adequate air supply is furnished in preheated conditionto the defiagrating fuel cloud, serves to accumulate the slag and assaid wall preferably is inclined toward the entrance opening of the airsupply, the slag is melted down from time to time and is cooled in smallmasses upon the bottom, from which it may bereadily removed. Undernormal operation of the furnace, the air supply cools a certainproportion of fine ash which falls to the bottom and may also be readilyremoved together with the small masses of slag. The inclined slagg'ingwall is so positioned and the deflagrating fuel cloud so directed, thatthere will be no impact and consequent accumulation of partly burnedfuel, accompanied otherwise by the rapid disintegration of theimpactedfurnace wall. Thus, at times it is desirable positively to direct theentering. fuel cloud so that the defia ating fuel may be properlypositioned wit in the combustion chamber and this is accomplished by anadjustable guide plate preferably associated with the fuel nozzle. Otherfeatures and the details of operation may be more readily explained bymaking reference to the accompanying drawings i1 'lustrating thepreferred apparatus for practicing and embodying my invention, where-'1n:'

Fig. 1 is a composite plan and horizontal SGC-tlOllttl view (thedrawings being somewhat diagrammatic in character because of the smallscale required) illustrating my improved furnace.

F g. 2 IS a vertical sectional view thereof on hne 2-2, Fig. 1. Fig. 2is a fragmentary section.

Fig. 3 is another verticalsection taken at right angles to that of Fig.2, on line 33, and

Fig. 4 is an enlarged sectional view of the fuel-supplying nozzle anddeflector.

Throughout the several figures, of the drawings similar parts areindicated by the same character of reference.

My invention is embodied and practiced preferably in a furnace ofvertical type wherein the pulverulent fuel is injected within thecombustion chamber by an air supply, generally in a downward direction,and is burned in a broad, reverting flame away from the bottom and wallsof the combustion chamber, by means of a partial air supply from aboveand a preheated combustion-supporting supply at and across the bottom ofsaid chamber. The furnace, as a whole, indicated by a, has an uprightcombustion chamber 12 communicating with a wide exit flue 0 near theupper portion of said furnace, and discharging through the controlledchimney stack 03 (Fig. 2 The associated boiler or other structuralfeatures are not shown, as these are unessential to the explanation ofmy invention.

Fig. 4 shows with some detail the preferred fuel-supplying nozzle anddeflector which are positioned in the upper portion of the furnace fordirecting downwardly within the combustion chamber. a thin, expandingfuel cloud. This comprises essentially, the pipe a for conveying the airblast of pulverulent anthracite or other desired fuel to a wide,flattened nozzle member a, giving initial direction, dimensions andretarded velocity to the entering fuel cloud or curtain. A hingeddeflector plate 6 is adjustably disposed before the passage 6'communicating with the nozzle and with the upper portion of thecombustion chamber; said deflector serving to direct the fuel cloudrearwardly within said chamber, whensuitably adjusted.

The casing e accommodating passage 6' and nozzle a is provided at itsupper level with shutter members f and f'- which are designed for use tocontrol the initial air supply for the fuel cloud. Member f alonenormally is open in theoperation of the furnace to furnish an inducedair supply to the interior of the reverting flame or loop of thedeflagrating fuel cloud. This initially is ignited by means of a woodfire on the, furnace bottom, or other suitable source of heat.

The main air supply for furthering and completing combustion is suppliedfrom the bottom of the furnace through rear openings 9 controlled by thehinged doors 9. When the fuel cloud has been burning in the combustionchamber sufficiently to establish an intense reverting flame, as shownin Fig. 2, the incoming fuel will be ignited by heat directlycommunicated therefrom, as it enters said combustion chamber closelyadjacent to the exit flue. Ignition takes place normally in the zone h,h and the air sup ply is directed across the bottom 5 by the ducts 9" sothat it enters forwardly of the fuel curtain and rising and expandingadjacent to the front wall of the furnace, turns downwardly with theentering fuel with which it mixes to support and complete combustion, asI have endeavored to indicate by the darts in Fig. 2.

The inclined slagging wall j necessarily becomes highly heated duringthe operation of the furnace and an accumulation of slag 7" will formthereon, which slag, upon forcing the furnace above its normal rating,will become viscid and fall from the lip or edge of said slagging wall jinto the path of the incoming air supply. Thus, said air supply servesthe double purpose of cooling the slag in small masses as it falls tothe bottom 11, while the air itself becomes preheated, therebyeconomizing the consumption of fuel. bhould the furnace be operated onlyat normal rating, it is requisite that the load carried by it shall betemporarily increased, say at two day intervals, in order to. melt theaccumulated slag from wall j and permit the masses of cooled slag formedon the bottom 2', together with the ashes also resulting fromcombustion, to be removed through the doors i. This melting down of theslag may best be accomplished in practice, if the furnaces are notnormally forced above their given rating, by forcing first one furnaceand then another of a series or battery of furnaces, while firing theothers below normal.

It is common experience, however, that furnaces must be forced duringthe peak or peaks of load each day, to several times their normalrating. My present invention, 1n providing the slagging wall justdescribed and in devising the method of operation, accordingly lendsitself to commercial conditions commonly met with, and, in particular,avoids the undesirable results otherwise attendant upon slagging undersuch conditions, or the alternative and impracticable construction offurnaces of excessive height as to the combustion chamber.

Under varying conditions of firing, it is also desirable to employpositive means for directing or positioning the fuel cloud within thecombustion chamber. The hinged detlectior plate '0 maybe inwardlyadjusted' when desired, usually under light or normal loads only, inorder to position the flame within the combustion chamber. In additionthereto, the force of the air blast may be varied, while the stackeffect may be used for controlling the air supplies, by opening orpartly closing the damper d. At times the shutter f in casing 6" mayalso be opened to afford an additional regulated air supply at the topof the combustionichamber. However, the regulated airgsupply through theopening controlled by shutter f ordinarily is suflicient. This a-ir"supply principally secures the continuing ignition of the entering fuelcloud and supports the combustion thereof interiorly of the loop orreverting flame.

Having now described means suitable for practicing and likewiseembodying my inwith vention, I claim as new and desire to secure byLetters Patent, together with such departures from method and structureas may be made merely by one skilled in the art, the following;

1. The herein described method of firing ulverulent fuels, whichconsists in directing such fuel downwardly at low velocity within thecombustion chamber, providing therefor a partial supply of air, causingthe deflagrating fuel to revertupwardly closely. adjacent to theentering fuel for subjecting it to an igniting temperature, furnishingan additional supply of air to com- .plete combustion ofthe fuel cloudin space adjacent to a. sla and the 0 eration, substantially as setforth.

2. heherein described method of firing with pulverulent fuels, whichconsists in ging surface, and melting directing such fuel downwardly atlow velocity within the combustion chamber, causing the deflagrating-fuel,to burn in space closely adjacent to an inclined slagging surface,melting the resultant slag and permitting it to drip to the bottom ofsaid chamber; meantime preheating a combustion-supporting air supply forthe fuel and thereby cooling thesla in such form as it ma be readilyhandle substantially as set fort 3. The herein described method ofdisposing of slag resulting from'the combustion of pulverized fuels,which consists in causing the deposit of the residues of combustion inthe form of slag upon an inclined slagging surface, melting the slag sothat it will drip from said surface in small masses, an aircooling suchdripping masses of slag sufliciently to prevent their cohesion,substantially as set forth. 7

4. In a furnace of the class described, the combination with itscombustion chamber, of an inclined slagging surface rearwardlypositioned within the combustion chamber, means for directing a fuelcloud diagonally downward within the combustion chamber towards saidinclined slagging surface,.and

means disposed at adistance below the for ward edge of said surface forcooling the slag as it flowstherefrom, substantially as set forth.

5. In a furnace of the class described, the combination with a verticalcombustion cooling the slag in small masses during inclined sag-receiving wall, and ducts positioned beneath said wall and extendingto openings adjacent to its forward lower portion, whereby a preheatedair supply may be furnished to the entering fuel cloud initially in areverse direction thereto, substantially as set forth.

7. In a furnace of the class described, the

combination with a vertical combustion chamber, of 'means for directinga fuel cloud downwardly from the upper portion and near thefront of saidchamber, a rearward forwardly sloping slagging wall provided in saidchamber with its lower edge disposed above the bottom of the combustionchamber, and means associated with said lower edge for cooling the slagand preventing material cohesion of the masses dripping from theslagging wall, .substantially as' set forth.

8. The herein described method of firing with pulverulent fuels, whichconsists in maintaining combustion thereof above a sharply inclinedslagging surface, permitting the slag to build up thereon, andthereaftermelting off and cooling the slag as it flows from saidsurface, substantially as set forth. I

9. The herein described method of firing with fuels productive of slag,which consists in maintaining combution of said fuel above an inclinedslagging surface, permitting the slag to collect thereon, and meltingand causing the flow of molten slag from said slagging surface from timeto time, substantially as set forth.

In testimony whereof I do now afiix my signature.

. CHARLES W, LOTZ.

